In our article in Pediatric Research, Volume 12, pages 801-804 (1978), we discussed the possibility that individuals who possess two defective genes causing them to be victims of cystic fibrosis, or asymptomatic genetic carriers having one abnormal gene produce a unique protein termed "Cystic Fibrosis Protein" (CEP). This CFP can be isolated using isoelectric focusing in thin layer polyacrylamide gels as described in the publication by Wilson, Jahn and Fonesca, Clin. Chim. Acta, Volume 49, page 79 (1973); G. B. Wilson et al. Pediatric Research, 9:635 (1975); and G. B. Wilson et al. Pediatric Research, 11:986 (1977). The Cystic Fibrosis Protein is characterized as a protein with an isoelectric point (pI) of 8.46.+-.0.05, and is found in more than 90 percent of individuals tested who are homozygous and heterozygous for the cystic fibrosis gene. However, the Cystic Fibrosis Protein is absent from 92 percent of normal control subjects tested under standardized and controlled conditions.
In accordance with this invention, a method is provided for diagnosing cystic fibrosis in patients and also diagnosing asymptomatic carriers of the cystic fibrosis gene, based upon the detection of Cystic Fibrosis Protein in the blood plasma or serum of patients. Frequently it has been found that the test of this invention can distinguish between those actively suffering from cystic fibrosis and asymptomatic carriers by the concentration of Cystic Fibrosis Protein present in the serum, as determined by the method of this invention.
Furthermore, it is preferred in the method of this invention to utilize a monospecific antibody to Cystic Fibrosis Protein. Methods are described herein for obtaining antibody to Cystic Fibrosis Protein and particularly highly purified, monospecific antibody formulations.